Project Title:

"A Compact Airborne Hygrometer for Commercial/Research Aircraft"

  94-1	08.05	1322

  "A Compact Airborne Hygrometer for Commercial/Research 
  Aircraft"

Abstract:

Southwest Sciences proposes the development of a compact 
laser-based hygrometer for commercial and research aircraft 
applications. The instrument dynamic range will encompass 
dew/frost points of +40@ C down to -90@ C and will be suitable 
for in situ measurements throughout the troposphere. Response 
times will be better than one second. The planned instrument 
detects absolute water vapor concentrations using optical 
spectroscopy with a near-infrared diode laser operating at 
1393 nm. Optical absorbance measurements are made using a 
novel electronic noise canceler capable of minimum detectable 
absorbances below 1 x 10-5. Fiber optics will eliminate all 
outside sources of water vapor and will permit a compact, 
rugged system. The Phase I experiments are expected to 
demonstrate the feasibility of this system for detecting water 
vapor accurately and rapidly over a nearly million-fold range 
of concentrations. The Phase II program will culminate in the 
delivery of a fully-automated commercial prototype hygrometer 
for airborne applications.

Compact, rugged airborne humidity sensors have commercial 
potential for aircraft ascent hazard indicators and local 
weather forecasting. These trace gas detection methods also 
can be adapted to a wide variety of other gases. Applications 
include continuous monitoring of chemical processes, open path 
monitoring of toxics, and on-line purity determination of 
process gases.

Key Words

Southwest Sciences, Inc.
1570 Pacheco St., STE E-11
Santa Fe, NM 87505